U
nIT
o
PTIons
www.DaikinApplied.com
63
IM 1058-8 • MAVERICK II ROOFTOP SYSTEMS
Variable Frequency Drive for VFD Compressor
WARNING
Never bypass the compressor drive or directly connect the
VFD compressor to the main power supply.
WARNING
The compressor drive is preset to run the compressor
clockwise.
WARNING
Variable Speed Inverter Compressor
The VFD is factory-programmed and should not be modified
in the field. Any modifications will void the warranty.
Compressors are compatible with the manufacturer’s VFD
only.
The compressor drive used for this option is a special series
(CDS 303) that is intended for use with an IPM compressor
motor and cannot be replaced with any off the shelf VFD.
The compressor drive is mounted in the main control box.
The compressor drive and the LCP (local control panel) are
preset with parameters from the factory and should not need
to be changed in the field. The LCP is removable and is
interchangeable with any of the compressor drives used by
any of the VFD compressors. If the need arises to replace the
compressor drive, the parameters can be downloaded from the
LCP to the new compressor drive.
The compressor drive is preset to run the compressor
clockwise and must be connected as shown in the unit
schematic.
The compressor drive is preset for an open loop configuration
with 0-10Vdc reference corresponding to 1500-6000 Rpm.
The compressor drive generates a soft start with an initial ramp
of 2 seconds. In-rush current (or LRA) to the VFD compressor
is typically not more than a few percent more than rated
nominal Current.
Compressor Speed, modulation signal %, frequency signal,
compressor amperage are all displayed in real time on the
compressor drive screen. Alarms and descriptions will also be
visible on the compressor drive screen.
Basic Operation of Compressor Drive:
Start=
Connect terminals 12 & 18 for minimum of 5 secs,
connect terminals 12 &27 and terminals 13 &37
Stop=
Disconnect terminals 12 & 27
Emergency Stop=
Disconnect terminals 13 & 37
Control/Modulation=
0 to 10Vdc signal to terminals 53 & 55
Run Verification=
A contact closure from relay 02 (terminals
04 & 05) is provided when drive is running
Oil Injection=
A contact closure from relay 01 (terminals 01 &
02) is provided when compressor speed is greater than 50 rps
(3000 rpm) which energizes the oil solenoid coil.
The compressor drive contains protection for the compressor
against short circuits at the compressor terminals, overload
protection , phase loss and earth faults. The compressor drive
is protected against short-circuits.
Table 29: Compressor Drive Model & Frame Size
Compressor
Model
Drive Model
Frame Size
208-230V
460V
VZH-088B
CDS303-15kW
B4
B3
VZH-117B
CDS303-18kW
C3
B4
VZH-170B
CDS303-22kW
C3
B4
Refer to the VFD operational manual for more information.